Present day radio frequency (RF) transponders use different modulations methods to convey information. The choice of these methods is usually a tradeoff between complexity, performance, reliability and cost.
For example, the utilization of coherent PSK within a communication link minimizes the transmitter peak power, but requires a high degree of frequency stability between the transmitter and receiver. In order to meet the frequency stability requirements, either a precision frequency source must be used at each end or a frequency tracking technique must be employed. If a burst mode communication system utilizing low-cost transmitters is required, neither of these two options are attractive. The use of precision frequency control devices is expensive and complex. The use of frequency tracking increases complexity and requires a portion of the timeline to be dedicated.